Here is a brief explanation of how A.M. Best rates insurance companies. You should strive to find a company that has at least an A rating and preferably an A+.
Best's A+ Superior
This is the highest grade an insurance company can achieve. Companies with a Best's A+ have a superior proven ability to meet their financial obligations with their policy holders.
Best's A Excellent
Companies in this classification also have an excellent financial performance. Not as strong as an A+ company but still more than capable of meeting their financial obligations.
Best's B+ Very Good
Again, going down the list....these companies have shown a "Very Good" ability to meet their financial obligations to their policy holders.
Best's B Good
Insurance companies with a B show a good ability to meet their obligations, but not as strong as the previous grades.
Best's C+ Fairly Good
Again, a fairly good overall performance.
Best's C Fair
And finally, a C means the insurance company has achieved a fair ability to meet their financial obligations.